UCLA Breast Cancer Survivor Health Promotion Research Study

Overview

Pilot randomized controlled parallel group behavior change comparative effectiveness trial involves 30 breast cancer survivors interested in losing excess body fat. Both interventions include dietary + exercise prescriptions that hold promise for reducing the survivors' risk of cancer recurrence. Both interventions are consistent with the Dietary Guidelines for Americans but the Diabetes Prevention Program (DPP)-based approach focuses on weight loss through calorie restriction and increased physical activity while the Highly Microbiota-Accessible Foods (HMAFs) approach is intended to be a low-numeracy version of a Mediterranean-style diet and increased physical activity. The DPP approach is considered to be a high-numeracy intervention because it requires that consumers keep track of all calories consumed and expended per day and to endeavor to maintain a calorie deficit each day during the active weight loss phase. For both conditions, the 12 to 13-week intervention includes 2 virtual home visits, 2 virtual group education sessions and 7 telephone or Zoom-based coaching sessions by well-trained intervenors. Assessments occur at baseline and six months, with systemic inflammation (high sensitivity C-reactive protein) being the primary outcome measure and visceral fat being a secondary outcome. Other prespecified secondary outcomes include gut microbiota alpha-1 diversity, insulin resistance, HDL-cholesterol, daily count of highly microbiota-accessible foods, waist circumference, BMI, systolic blood pressure, ratio of fecal Proteobacteria to short chain fatty acid-generating bacteria and health-related quality of life.

Background. The human gut microbiota influences obesity status and inflammation, two major risk factors for postmenopausal breast cancer recurrence. Whether an exercise and dietary intervention designed to optimize gut microbiota composition might reduce risk for breast cancer recurrence is unknown. To improve the gut microbiota composition, the investigators propose teaching postmenopausal breast cancer survivors to allocate about 20% of their daily calorie intake to consuming a daily count of six fiber-rich, minimally processed, plant-based food choices that comply with federal MyPlate.gov diet recommendations. Preliminary data suggest that the investigators' Highly-Microbiota-Accessible Foods (HMAFs) approach will yield cardiometabolic outcomes equal to or better than those achieved by the traditional Diabetes Prevention Program (DPP) calorie restriction approach at 6 months follow-up. Because breast cancer recurrence risk covaries with cardiometabolic risks, the lower cardiometabolic risk of the HMAFs approach should be associated with reduced risk of breast cancer recurrence. Hypotheses. The greater diversity of fiber-rich, minimally processed plant foods consumed in the HMAFs condition relative to the DPP condition will result in greater changes in HMAFs participants compared to DPP participants from baseline to 6 months follow-up in the following measures: (primary hypothesis) reduce high sensitivity C-reactive protein, (secondary hypotheses) reduce visceral body fat and increase alpha-1 diversity of gut microbes and increase health-related quality of life. To test these hypotheses, the research objectives include the following specific aims: 1) Recruit a diverse sample of 30 overweight or obese postmenopausal survivors with stage I, II and IIIa breast cancer; randomly allocate them to two lifestyle change intervention conditions, 2) Obtain baseline and 6-month follow-up assessments of: low grade systemic inflammation, body composition including visceral fat estimation, cardiorespiratory fitness, inflammatory and cardiometabolic biomarkers, fecal samples, and quality of life, 3) Conduct two parallel, three-month behavior change interventions, contrasting the 6-count HMAFs approach with the traditional DPP calorie restriction approach , and 4) Use results to design a ramped-up randomized factorial trial. If hypotheses are confirmed, the low-numeracy HMAFs approach may, for low-income survivors, be a practical alternative to traditional high-numeracy calorie restriction approaches to reducing risk of breast cancer recurrence.